GM Metro/Sprint 1985-1993 Repair Guide



See Figure 1

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Fig. Fig. 1: Cruise control system components

The cruise control system consists of an mode control switch, electronics module, servo unit, speed sensor and wiring harness. Throttle actuation is accomplished by an electrically operated servo motor attached by cable to the vehicles throttle linkage. Maximum and minimum cruise speeds are 85 and 25 miles per hour.

The vehicle speed is provided to the electronics module by the use of a speed sensor. The sensor utilizes a magnetic reed switch which opens and closes 4 times per revolution of the speedometer cable. The sensor is located in the speedometer head.

The electronics module is the brain of the system. The module interprets the position of the servo unit, the position of the mode control switches and the output of the speed sensor. In response to these inputs, the module electrically signals the servo motor drive in or out. The electronic module is located under the dash on the driver side.

The disengagement switches, brake and clutch, are operated by the use of the brake and clutch pedals. The brake switch operates the stoplights and cancels the signal to the cruise control module when the lights are illuminated. The clutch switch disengages the cruise control if the pedal is depressed for up shifting or down shifting.

The servo consists of an electric motor with reduction gearing, electromagnetic clutch, actuating rack and a variable voltage position sensor. The servo operates the throttle in response to signal from the electronics module.

If vehicle is equipped with an supplemental inflatable restraint system (SIR), the system must be fully disarmed before performing cruise control repairs. Failure to disarm the system could result in personal injury and/or property damage.